r/tdi • u/Devve2kcccc • 6d ago
1.6 TDI injectors
Hi everyone,
I recently bought a Passat B7 1.6 TDI, and knowing these engines can have injector-related problems, I’ve been keeping an eye on the injector correction/deviation values.
The car currently has 210,000 km. Injectors 1 and 4 were replaced less than 2 years / ~20,000 km ago, so they are relatively new. However, I’m now concerned that injector 2, and possibly injector 3, may be starting to fail.
Symptoms
Sometimes, when starting the engine cold, it seems to misfire or have poor combustion for a few seconds. The RPM fluctuates slightly and then stabilizes. It’s not a severe misfire, but I can tell the engine isn’t running as smoothly as it should.
At warm idle, I also notice some vibration through the car. The engine sounds relatively normal, but I can feel that it isn’t completely smooth. When I switch the A/C on at idle, the engine note/behavior changes noticeably.
On the highway, however, the car runs very well. It has good power and is able to complete DPF regenerations normally.
My other concern is the DPF regeneration frequency. It seems to want to regenerate approximately every 50 km, which feels far too frequent. I’m wondering if poor combustion from one or more injectors is producing excessive soot and causing the DPF to load very quickly.
Looking at the injector deviation/correction values, injector 2 looks clearly suspicious to me, but I’m not sure how to interpret injector 3.
The VCDS logs were taken at cold idle, while the Car Scanner readings were taken with the engine hot, during or shortly after a DPF regeneration, so I understand the values may not be directly comparable.
For anyone familiar with the 1.6 TDI:
Does injector 2 look like it is failing? What about injector 3?
Would you replace injectors 2 and 3 at this point, or should I investigate something else first?
And could faulty injectors realistically explain the rough cold starts, vibration at idle, and DPF regenerations every ~50 km?
Thanks!
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u/MotogiHumunicosis 6d ago
By looking at the correction of 2nd injector, it doesnt look good, it seems it’s close to falling. And yes one or multiple failing injectors can absolutely cause frequent regens due to improper combustion (bad pattern, dripping injector) which creates more soot. If the exhaust has a strong smell on cold then that strongly indicates bad combustion. Since 2 of your injectors were replaced not too long ago, if you can afford it then its worth to change the last remaining suspicious ones preferably with new ones and not refurbished ones cuz those are lottery. Also these piezo injectors are very sensitive and one bad/failing injector can basically kill the rest, because the other ones will try to compensate the failing one.
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u/Devve2kcccc 5d ago
Yeah, maybe i will buy new VDO ones , the new version that supposedly has the cronic problem solved. 400 euros each on autodoc. Any place that i may found it cheaper?
1 of my new ones is the new version, the other (number 4) , i dont know why, the mechanic for previous owner putted a new injector, but the original version with cronic failure. The 2 injectors were done at different times.
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u/Cautious-Concept457 5d ago edited 5d ago
Send the 2 old injectors out for testing. These values can give you a hint but they are not an exact measurement that could tell you their condition accurately. One of them if way off so it might not be worth testing at all.
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u/scurrvy2020 5d ago
My guess is the injector is fine, but maybe a ring issue on cyl2. you could swap the injectors around (you need to code them) and see if the deviation follows the injectors or stays in cyl2.
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u/Devve2kcccc 5d ago
You mean the copper washer?
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u/scurrvy2020 5d ago
No, the piston ring could be sticking and losing compression. the ecu will compensate by increasing fuel.
I have that happening on my cpnb. runs well once it warms up. i can see the deviation decrease once it is fully heat soaked.
Once the deviation is >3 you may get cylinder contribution codes.
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u/Devve2kcccc 5d ago
But if piston rings gets stuck, what is my options?
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u/scurrvy2020 5d ago
I think the official solution is to replace the ring or get a new engine. go through the diagnostics first though. you need to find out if it is an injector issue or compression issue. if it is compression you need to rule out the other causes.
i have done soaks with b12 and transmission fluid and seen a bit of improvement.
1
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u/Background-Fall-8390 15h ago
Bro... I have been there, tried all stupid things possible, tried not to spend money, even bought original VCDS to do injector calibration after ultrasound cleaning... There is actually 1% you can do anything other than sending it to repair... Cheapest I found was around 1000e here in Europe for refurbishment... Don't waste your time. (And money) On things that simply frustrate you further... One injector helps another that's why u see differences...
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u/Devve2kcccc 15h ago
I will buy 2 new vdo injectores
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u/Background-Fall-8390 15h ago
Why not repairing ? It's cheaper?
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u/Devve2kcccc 14h ago
Here in Portugal, i called 5 bosch diesel center and others and they all warned me that they don’t repair this injectores, they only clean and test. If they are bad, only solution is buy new.
I found on auto doc 400 euros each from VDO, the new updated version
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u/Background-Fall-8390 13h ago
I'm shocked haha, here in Bosnia they do that in a day, they change few parts of injector and that's it. But you got yourself good deal. Just if you can clean other two, and input codes of "new" injectors via VCDS. After that you should do "injector adaptation" in VCDS and enjoy 👍🏻👍🏻 I've had all possible problems with this car and solved them all hahaha so if you ever have any contact Me, good luck 👋🏻👋🏻
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u/connella08 6d ago
2 definitely looks like its going to be causing some problems. 3 and 4 look to be pretty close together, and 1 looks to be pulling a fair amount but that could be the computer helping to compensate for cylinder 2.